Trouble with VFE Tractor beam

[john]

Having some trouble with my Tractor beam circuit. I built the main PCB, and when testing it I do get some phasing when the sweep trim pot is all the way CCW, but nothing like the tones I hear on the pedal demos. A lot of settings produce feedback and loud screeching howls, and I can't even turn the "mix" control past noon without encountering major feedback. I'm wondering if I have to first hookup the switch control board for this thing to work properly? I tested it by simply hooking up the in, out and ground connections to my 1/4" jacks, and giving power directly to the V+ and V- on the main PCB as I do with al of my other non-VFE builds when testing before boxing. I keep thinking there is a grounding issue but can see no trouble on the PCB. Wondering if this this feedback is normal for this build? Am I missing something basic here?

Thanks!

[zgrav]

the switching board for the VFE pedals also filters the power supply and contains the charge pump for the pedals that use it (like the Tractor Beam).  So at the very least you are getting less filtering on the power supply and the voltages going to your board may be different.  Check the TB build document for the voltage readings you should be getting on your pcb and compare them to your readings.  That may help you isolate the issues you are having.  I

[john]

Ok i see, well let's hope that's what it is. Gonna attach the switching board tonight once I receive the needed parts. I did take readings of the op amps and my voltages are definitely different from the build document's.

Thanks

[john]

Well if there was any doubt, the phaser circuit requires that the  switching board be attached as a power converter/voltage regulator, and wow! This is really one of the most creamy interesting sounding phasers I've come across.

Thanks again!

[zgrav]

Glad you got it working.